The core problem and solution of CB design (II)

Capacitor is also an important problem in circuit board design because capacitance will affect the speed of signal propagation and increase the consumption of electricity. The channel is coupled to the next circuit or perpendicular to the two layers, thus inadvertently forming a capacitor. By reducing the length of parallel lines and adding kink to one of the lines to cut off the coupling, the above problems can be solved relatively easily. However, it is also necessary for engineering designers to take full account of the production design principles, to ensure that the design is easy to manufacture and to avoid any noise radiation caused by excessive bending angle of the line. The distance between lines may also be too close, which will result in short loops between lines, especially at the bend of the line, and metal whiskers will appear over time. Design rule detection can usually indicate areas where the loop risk is higher than normal.

This problem is especially prominent in the design of grounding layer. A metal circuit layer may be coupled to all lines above and below it. Although the metal layer can effectively block the noise, the metal layer will also produce associated capacitance, which will affect the speed of the line and increase the consumption of electricity.

As far as the design of multilayer circuit board is concerned, the design of through hole between different layers of circuit board is probably the most controversial problem, because the through hole design will bring a lot of problems to the production and manufacture of circuit board. The through hole between the layers of the circuit board will affect the performance of the signal and reduce the reliability of the circuit board design, so we should pay more attention to it.

Solution: in the design process of printed circuit board (PCB), many different methods can be taken to solve various problems. There are not only the adjustment of the design scheme itself, such as adjusting the layout of the circuit to reduce the noise, but also the layout of the printed circuit board. Design components can be installed automatically through the layout tool, but if the automatic layout can be manually adjusted, it will help to improve the quality of circuit board design. Through this measure, the design rules will be checked with the help of technical documents to ensure that the design of the circuit board can meet the requirements of the PCB manufacturers.

Separating the different layers of the circuit board can reduce the associated capacitance, but this will increase the number of layers of the circuit board, thus increasing the cost and causing more problems in terms of through holes. Although the use of orthogonal power supply system and grounding circuit design may increase the physical size of the circuit board, but it can effectively exert the utility of the grounding layer in the double-layer circuit board, and reduce the complexity of the production and manufacture of the circuit board.

Many PCB design tools can help engineers solve many problems at the beginning of design, but engineers still need to have a good understanding of the design requirements of printed circuit board (PCB). For example, if an editor of a printed circuit board (PCB proofing) needs to know the number of layers of a circuit board at the beginning of the design, for example, a double-layer circuit board, it needs to have a connecting layer and a power layer. Two independent laminates are formed. Component automatic layout technology is of great use to help designers spend more time designing the layout area of a device, for example, If the power supply equipment is too close to the sensitive signal line or the higher temperature area, there will be a lot of problems. Similarly, signal lines can be automatically wired while avoiding most of the problems, but analysis and manual manipulation of high-risk areas will greatly improve the quality of (PCB) design for printed circuit boards. Increase revenue and reduce overall costs.

Design rule detection is also a very powerful tool, which can detect the lines to ensure that the distance between the lines is not too close, resulting in the circuit too short. However, the overall design still has high economic value. Design and test tools can also be used to detect and adjust the power layer and the grounding layer to avoid the generation of large associated capacitance areas.

The tools will also be of great help to Gerber and Excellon in their work on wiring and circuit board printing and through hole drilling in order to produce the final design product. In this way, the technical documents and circuit board manufacturers are closely linked.